(1) Field of the Invention
This invention is concerned with a machine suitable for operating progressively along marginal portions of shoe bottoms, comprising a shoe support, a tool carrier, means for effecting relative movement, both lengthwise and widthwise of the bottom of a shoe supported by the shoe support, between the shoe support and the tool carrier, and means for controlling the heightwise position of the tool carrier relative to the shoe support, as relative lengthwise and widthwise movement is caused to take place therebetween, so that, in an operating mode of the machine, the tool carrier can follow a pre-determined path, determined according to the contour of the shoe bottom being operated upon, relative to the shoe support, and a tool carried by the tool carrier can thus be caused to operate progressively along a marginal portion of the bottom of a shoe supported by the shoe support, wherein the tool is mounted on the tool carrier for limited movement relative thereto in a direction extending heightwise relative to the shoe support.
(2) Prior Art
One such machine is disclosed in U.K. patent specification No. 1,071,761. In this machine a three-dimensional template is located in a fixed relationship with the bottom of a shoe supported by the shoe support and the shoe support is caused to move lengthwise of the shoe bottom to carry the bottom of a shoe supported thereby past two tools each supported by a tool carrier, each tool carrier having associated therewith template following means which engage with opposite side portions of the template and thus cause the tools to be moved widthwise and heightwise of the path of movement of the shoe support, as the shoe support is thus moved. Furthermore, in said machine each tool is mounted for pivotal movement about an axis extending widthwise of the shoe bottom stop means being provided for limiting the downward movement of each tool towards the shoe bottom.
In using said machine the three-dimensional template, selected to suit the shoe bottom being operated upon, thus guides the tools, arranged in tandem relationship, along opposite side portions of the shoe bottom during relative lengthwise movement between the shoe support and tool carrier, any irregularities in the shoe bottom, as compared with the contour of the template, being accommodated by the facility for pivotal movement of the tool on the carrier. A disadvantage of this arrangement, however, resides in that a different template is required for each style and size of shoe, and indeed in each style and size, separate templates are required for left and right shoes. Bearing in mind that a shoe factory may well be processing upwards of a dozen styles of shoe, in all the sizes, at any given time, this requirement for individual templates for each style, size and hand clearly renders the use of such a machine unattractive, not least because of the problems of template storage.
The shoe bottom contour is of course a relatively complex one, and thus the use of a three-dimensional template is advantageous to the extent that it can be relatively easily reproduced direct from the shoe bottom, without the need for any complicated calculations. Because the problems referred to above are considered to outweight this one advantage of manufacture, however, there has been a move away from such three-dimensional templates: see e.g. U.K. Pat. No. 1,137,254, in which flat (i.e. two-dimensional) templates are used.
This change from three-dimensional templates has meant that the machine can itself be used in the manufacture of templates, the arrangement being such that, with a blank template carried by the template supporting means, a tool is moved relative to the shoe bottom by the operator, along a path determined by him, and an associated scribing tool, replacing the template follower, is caused to track over the surface of the blank template and score an appropriate line thereon. The template can thereafter be cut along the line to provide the desired shape. Such a procedure is also referred to in U.K. patent specification No. 1,137,254.
Such a procedure can be readily applied in the machine described in the last-mentioned patent specification, since there is no control of the heightwise position of the tool, other than by engagement with the shoe bottom.
It is the object of the present invention to provide an improved machine suitable for operating progressively along marginal portions of shoe bottoms, wherein the tool carrier is caused to follow a predetermined path not only lengthwise and widthwise but also heightwise in relation to the shoe support, the tool is mounted on the tool carrier for heightwise movement relative thereto, thus to accommodate any irregularities in the shoe bottom being operated upon as compared with the pre-determined path, and further means is provided for determining the path of the tool carrier in the machine.
The invention thus provides a machine suitable for operating progressively along marginal portions of shoe bottoms, comprising a shoe support, a tool carrier, means for effecting relative movement, both lengthwise and widthwise of the bottom of a shoe supported by the shoe support, between the shoe support and the tool carrier, and means for controlling the heightwise position of the tool carrier relative to the shoe support, as relative lengthwise and widthwise movement is caused to take place therebetween, so that, in an operating mode of the machine, the tool carrier can follow a pre-determined path, determined according to the contour of the shoe bottom being operated upon, relative to the shoe support, and a tool carried by the tool carrier can thus be caused to operate progressively along a marginal portion of the bottom of a shoe supported by the shoe support, wherein the tool is mounted on the tool carrier for limited movement relative thereto, in a direction extending heightwise relative to the shoe support, characterized in that the means for effecting relative lengthwise and widthwise movement between the shoe support and tool carrier comprises first and second numerically controlled motors (as herein defined) and the means for controlling the heightwise position of the tool carrier relative to the shoe support comprises a third numerically controlled motor (as herein defined), each such motor operating under the control of computer control means by which drive signals are generated and supplied to said motors in accordance with a programmed instruction, including digitized co-ordinate axis values, using three co-ordinate axes, for a plurality of selected points along the marginal portion of the bottom of the or a similar shoe, in that path-determining means is provided which is operable in a path-determining mode of the machine, and which comprises a manually operable control device for causing relative movement to take place along said three co-ordinate axes between the shoe support and tool carrier to bring them to successive selected points along the marginal portion of the bottom of a shoe supported by the shoe support, and means for digitizing, and storing in digitized form, the co-ordinate axis values of each such selected point, and further in that resilient means is provided for urging the tool to move relative to the tool carrier in a direction extending heightwise relative to the shoe support into a defined heightwise position in relation to the tool carrier and sensing means is also provided, operable in the path-determining mode of the machine, for sensing when the tool is in said defined heightwise position.
The term "numerically controlled motor" where used herein is to be understood as indicating a motor the operation of which is controlled by control signals supplied thereto in accordance with stored information appropriate to a desired operation. Examples of such motors are stepping motors and d.c. servomotors.
By providing such a control arrangement, displacing the three-dimensional template, the problems of storage of the latter are significantly minimized. Of course, it is still necessary for the digitized information to be stored, but this presents no significant problem in terms of space. Furthermore, by simple reversing and grading programs, which can be provided in the computer control means, from one set of digitized information each size of shoe in a given style can be accommodated and also left and right shoes in said style. Furthermore, by using the machine for determining the path of the tool, although the tool is mounted on the tool carrier for limited movement relative thereto heightwise of the shoe support, nevertheless by the sensing means being provided no problem arises in the path-determining mode of the machine from the tool being incorrectly placed heightwise in relation to the shoe bottom.
Preferably in the machine in accordance with the invention the resilient means is effective to urge the tool in a direction towards the shoe support. Furthermore, it is desirable that the pressure applied to a shoe bottom by the tool, as it operates progressively along a marginal portion of such shoe bottom, is controlled. To this end, therefore, in accordance with the invention, preferably also, in the operating mode of the machine, the tool is displaced, against the action of the resilient means, out of its defined heightwise position in relation to the tool carrier and thus the presser applied thereby is controlled by the resilient means.
One manner in which such displacement can be achieved would be for the co-ordinate axis values for each selected point to be digitized, in the path-determining mode of the machine, with the tool in its defined heightwise position, while in the operating mode of the machine the pre-determined path of the tool carrier relative to the shoe support is transposed in relation to, and towards, the shoe support. Where the tool is a roughing tool, however, such a system of transposition may be undesirable in that, at the start of the operating cycle, the tool would, as it approaches the shoe bottom but is not yet in engagement therewith, be disposed in its defined heightwise position and thus the shoe bottom engaging portion of its operating surface would be disposed below the level of the shoe bottom, with a result that the shoe upper may be roughed above its feather line as the tool engages the side of the shoe and is moved over its edge onto the shoe bottom.
Consequently in a preferred embodiment, in the path-determining mode, each selected point is determined in relation to the defined heightwise position of the tool, the tool carrier being thereafter moved heightwise through a distance to displace the tool from its defined heightwise position prior to the co-ordinate axis values of the selected point being digitized. As a further feature of such a procedure, such displacement is arranged not to take place at the first selected point, so that, e.g. in the case of a roughing tool, the tool is positioned directly at the height of the shoe bottom at the start of roughing.
Such displacement may be effected under the direct control of the operator. Alternatively, the procedure lends itself to automatic execution.
The resilient means may be fluid pressure operated and may further comprise variable pressure regulating means, the arrangement being such that the pressure applied to a shoe bottom by the tool is thus controlled by the pressure regulating means. In such a case, furthermore, means may be provided whereby the pressure controlled by said regulating means, and thus also the pressure applied as aforesaid to the shoe bottom, can be varied during the progressive operation of the tool along the marginal portion of the shoe bottom as aforesaid. In this way, where e.g. the shoe upper requires different treatments along its length, e.g. in the case of a roughing operation where the material of the upper is of different properties along its length, changes in pressure may be programmed into the computer control means at the same time as digitizing takes place.
The sensing means referred to may be arranged to prevent digitizing from taking place unless the tool is in its defined heightwise position. Alternatively, and preferably, however, the sensing means causes indicator means to be operated whereby a signal is provided, visible by the operator, when the tool is in its defined heightwise position and when moved therefrom. In this way, the operator can more readily ascertain when the tool has moved into its defined position. The sensing means may be of any conventional type, e.g. fluidic.
In one embodiment of the invention, the tool is a rotary tool, more especially a radial wire roughing brush, said tool being carried on an arm which is supported on the tool carrier for pivotal movement about an axis extending generally lengthwise of the shoe bottom and on which the resilient means is arranged to act, belt drive means being provided for rotating the tool, including a pulley mounted for rotation about said axis. By this arrangement, the heightwise movement of the tool in no way affects, or is affected by, the means for effecting rotation thereof.
With such a tool, furthermore, grinding means may be provided, as is conventional, whereby the operating surface of the tool can be ground. In such a case, means is also provided for shifting the defined heightwise position of the tool in relation to the tool carrier through a pre-determined distance each time a grinding operation takes place. The shifting means may conveniently also comprise a numerically controlled motor (as herein defined).
For ensuring that, during the grinding operation, the tool is located in a known position (which is necessary where the tool operating surface is maintained at a datum), the tool may be urged into its said defined heightwise position, to which end increased pressure is applied to and acts upon the resilient means, such pressure being sufficient to resist any counter-pressure as the grinding means is urged against the operating surface of the tool. Alternatively, the tool may be moved during the grinding operation into a second defined heightwise position spaced from said first-mentioned defined heightwise position. This can be readily achieved in accordance with the invention in that the end of the arm remote from its axis of pivot is connected to the tool carrier by a pin-and-slot connection, which thus defines the first-mentioned and second defined heightwise positions of the tool in relation to the tool carrier.
Preferably the tool carrier is mounted for pivotal movement about an axis extending widthwise of the shoe bottom, the tool being so arranged that said axis extends tangentially, or substantially so, to the shoe bottom engaging portion of its operating surface, when the tool is in contact with the shoe bottom being operated upon. Furthermore, preferably means, including a numerically controlled motor (as herein defined), is provided for effecting pivotal movement of the tool carrier about said axis as the tool is caused to operate progressively along the marginal portion of the bottom of a shoe, said motor also operating under the control of computer control means in response to drive signals generated and supplied thereto by said computer control means in accordance with a programmed instruction.